"It will send a strong signal to all companies that they will be held accountable," he wrote on his Facebook page after the system was approved by the 10-nation Association of Southeast Asian Nations at a summit in Brunei.

Several big palm oil companies have been accused of lighting fires on their concessions to clear land in Indonesia's Sumatra island.

The Roundtable on Sustainable Palm Oil has said it would investigate some of its members over the allegations.

The group—which produces a sought-after certification for producers deemed sustainable—bans its members from using burning to clear land.

In June Singapore and Malaysia were blanketed by the putrid, choking smog for days, affecting tourism, forcing schools to close and causing a rise in respiratory illnesses.